Unbiased contaminant removal for 3D galaxy power spectrum measurements

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dc.contributor.author Kalus, B.
dc.contributor.author Percival, W. J.
dc.contributor.author Bacon, D. J.
dc.contributor.author Samushia, Lado
dc.date.accessioned 2017-12-12T20:40:17Z
dc.date.available 2017-12-12T20:40:17Z
dc.date.issued 2016-08-15
dc.identifier.uri http://hdl.handle.net/2097/38451
dc.description Citation: Kalus, B., Percival, W. J., Bacon, D. J., & Samushia, L. (2016). Unbiased contaminant removal for 3D galaxy power spectrum measurements. Monthly Notices of the Royal Astronomical Society, 463(1), 467-476. doi:10.1093/mnras/stw2008
dc.description.abstract We assess and develop techniques to remove contaminants when calculating the 3D galaxy power spectrum. We separate the process into three separate stages: (i) removing the contaminant signal, (ii) estimating the uncontaminated cosmological power spectrum and (iii) debiasing the resulting estimates. For (i), we show that removing the best-fitting contaminant (mode subtraction) and setting the contaminated components of the covariance to be infinite (mode deprojection) are mathematically equivalent. For (ii), performing a quadratic maximum likelihood (QML) estimate after mode deprojection gives an optimal unbiased solution, although it requires the manipulation of large matrices (N-mode being the total number of modes), which is unfeasible for recent 3D galaxy surveys. Measuring a binned average of the modes for (ii) as proposed by Feldman, Kaiser & Peacock (FKP) is faster and simpler, but is sub-optimal and gives rise to a biased solution. We present a method to debias the resulting FKP measurements that does not require any large matrix calculations. We argue that the sub-optimality of the FKP estimator compared with the QML estimator, caused by contaminants, is less severe than that commonly ignored due to the survey window.
dc.relation.uri https://doi.org/10.1093/mnras/stw2008
dc.rights © 2016.This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
dc.rights.uri https://academic.oup.com/journals/pages/access_purchase/rights_and_permissions/self_archiving_policy_p
dc.rights.uri http://rightsstatements.org/vocab/InC/1.0/
dc.subject Methods: Statistical
dc.subject Large-Scale Structure Of Universe
dc.subject Redshift Surveys
dc.subject Systematics
dc.subject Astronomy & Astrophysics
dc.title Unbiased contaminant removal for 3D galaxy power spectrum measurements
dc.type Article
dc.date.published 2016
dc.citation.doi 10.1093/mnras/stw2008
dc.citation.epage 476
dc.citation.issn 0035-8711
dc.citation.issue 1
dc.citation.jtitle Monthly Notices of the Royal Astronomical Society
dc.citation.spage 467
dc.citation.volume 463
dc.contributor.authoreid lado
dc.contributor.kstate Samushia, Lado

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